• Factory produced modules, ensuring economies of scale and potentially eliminating the major up-front capital costs of nuclear reactors
  • Passive safety systems to provide enhanced security
  • Ability to fit easily into most electricity grids around the world
  • Ordered ‘just in time’, once demand is assured
  • Constructed and installed quickly, thus reducing investor risks
  • Factory built, shipped to site
  • Manufactured on production lines like aircraft, turned out rapidly and with good quality control
  • More competition between more manufacturers leads to faster rate of improvement
  • Reduced requirements for technical workforces to install and maintain power plants; and
  • A wider range of deployment options, including remote locations and specific purpose energy generation, such as desalination plants

 

“We see SMRs as having enhanced safety and security attributes; the safety largely due to the lower power levels and the greater ability to rely on passive heat-removal systems. Certainly we expect them to come in at a lower cost which makes them more affordable and more feasible for a large number of utilities. Shorter construction schedules are also a potential benefit due to modular construction. Factory fabrication also offers the capability to improve the quality of the product and replicate it in factory setting. And as electric demand increased incrementally, we expect the SMRs to be able to fill that market. The market space is great, both domestically and internationally. We see a large need over the next several decades to replace fossil-fuel plants, and these small reactors have an opportunity to either replace or repower as we retire those units."

– John Kelly, Deputy Assistant Secretary, Nuclear Reactor Technologies, Department of Energy, Office of Nuclear Energy, addressing the U.S. Nuclear Regulatory Commission, Briefing on Small Modular Reactors in March 2011, Transcript – page 5

Cutaway of a Westinghouse 225 MWe SMR
Source: Westinghouse

Nuclear power technology – background

Nuclear power plants have been generating reliable base-load electricity with low greenhouse gas emissions since the 1950s. Historically nuclear power plants have been built larger and larger. This was to obtain economies of scale in deployment to overcome the high fixed construction costs. As a consequence, modern nuclear power plants incurred substantial financing costs and required large, well connected electricity grids.

Currently there are 433 power reactors operating in 31 countries supplying ~14% of the world’s total electricity demand. Modern power reactors typically have an output of >1,000MW electrical which is too large for small countries or small grid systems.

The International Atomic Energy Agency (IAEA) defines “small" as less than 300 MWe but many SMRs have outputs in the range 25-100 MWe.

The future of nuclear power stations: Small Modular Reactors

A market is developing for smaller reactors – in particular for SMRs, which can supply low-emissions, high capacity factor, and reliable power in remote locations or for small grid systems. They represent a new stage in nuclear reactor design and have the capacity to provide an economically competitive method of electrical power generation.

There is extensive experience of much of the technology employed by SMRs. For many years they have been the power supply for submarines and icebreakers, where totally reliable power with long periods between refuelling is essential.

Features of Small Modular Reactors

Depending on the technology, many SMR designs can incorporate the following features:

  • Power in remote locations where transport of fossil fuels for conventional electricity generating plant is expensive
  • Base load power for small grids
  • Near zero emissions
  • Compact – small site area per kW installed capacity, with reduced siting costs
  • Modules easily added as extra capacity is required
  • Electricity, steam and co-generation
  • Balance of plant equipment comprising conventional off-the-shelf steam turbine/alternator, pumps and electrical systems
  • Turbine condenser that can be air-cooled in remote locations where water supplies are restricted
  • Reliable, high capacity factor, not affected by weather conditions
  • Compact factory-built transportable modules
  • Economy and high quality of factory mass production of a simple, standard design
  • Main modules are factory built, minimising on-site construction time costs and reducing the risk of project delays
  • Simple design to operate and maintain (lower maintenance costs for passive systems)
  • High level of passive or inherent safety
  • Reactor modules delivered with the fuel already installed, eliminating the need for initial fuel loading on site (some designs)
  • Long periods between refuelling (can be years, up to 30 years for some designs)
  • Sealed core which is returned to the factory for refuelling, reducing the possibility of unauthorised interference with
  • nuclear materials (proliferation resistant, some designs)
  • Low and stable fuel costs (fossil fuel costs, particularly gas, are expected to continue to rise). Nuclear power is a hedge against the price volatility of fossil fuels
  • Fuel costs typically only 25 per cent of the production costs
  • Smaller initial capital investment compared to a large reactor
  • Sixty year life
  • Reactor containment can be installed below ground providing additional protection against external hazards and unauthorised interference